1. Field of the Invention
This present invention relates generally to a universal joint and particularly for use with an agitator and a fixing device thereof, and more particularly to an agitator having a chuck and a chuck cover, and to a fixing device for a universal clamp for fixing an agitator or the like to a supporting post at an arbitrary angle.
2. Description of the Prior Art
A conventional agitator disclosed in the Japanese Utility Model Registration No. 3010021, for example, comprises a main body of an agitator, rotary shaft, a chuck for connecting said rotary shaft with an agitating rod, and a chuck cover, wherein the chuck is covered with the chuck cover so as to prevent the hair of an operator or the like from being caught by the chuck when the chuck is rotated.
According to the conventional agitator having the chuck cover, there is no such a problem that the hair of the operator is caught by the chuck when the chuck is rotated. However, such problem cannot be solved when the chuck is not closed with the chuck cover perfectly and any device for stopping the agitator when the chuck is not closed with the chuck cover perfectly is not provided.
Further, a universal clamp for fixing physical and chemical appliances or the like to a supporting post is disclosed in the Japanese Utility Model Publication Laid-Open No. 39130/94. Such universal clamp comprises a main body, a supporting post for supporting the physical and chemical appliances, a spherical member provided on the tip end of the supporting post, a pair of holding elements for forming a spherical member supporting portion of a diameter identical substantially with or smaller than that of the spherical member, a wedge member arranged at one side of said spherical member supporting portion movably in the vertical direction, and a threaded member provided at an upper portion of said main body in order to urge said wedge member downwards to move one of said pair of holding elements toward the other of said pair of holding elements.
According to the conventional universal clamp, one of the holding elements is moved horizontally toward the other of holding elements by a horizontal component of force generated when the threaded member is rotated and thus the wedge member is moved downwards. As a result, there is such a problem that a force for holding the spherical member is small and that a large holding power cannot be obtained.
An object of the present invention is to provide a universal joint comprising a joint case to be mounted on a supporting post a cavity formed in the joint case, an elongated groove formed at the upper portion of the cavity, a planar plate fitted in the elongated groove, a spherical surface receiving seat for closing the cavity, a spherical member arranged in the cavity so that it is held by the seat and a portion of the planar plate deviated from the center of one surface of the planar plate toward the other side of the joint case, a ball shank, one end of which is connected to the spherical member and the other end of which is extended to the outside of the joint case and pressure means for pressing the other end of the planar plate toward the spherical surface receiving seat.
Another object of the present invention is to provide the universal joint, wherein the pressure means is a screw to be threaded in the joint case, one end of which is brought into contact with the other end on the other surface of the planar plate.
The other object of the present invention is to provide the universal joint, wherein the spherical surface receiving seat is threaded detachably in the joint case.
These and other objects and features of the present invention will become apparent from the following description in conjunction with the attached drawings.